Duong–Quy S, et al. – This cross sectional and descriptive study aimed to explore the cutoff of nasal fractional exhaled nitric oxide (FENO) in the diagnosis of subjects with allergic rhinitis (AR) and AR–asthma compared to age–matched subjects without AR or asthma and its correlations with the clinical and functional characteristics. The authors concluded that nasal FENO measurement was a beneficial technique for the diagnosis of AR in subjects with and without asthma.